The invention relates to devices for varying the size of headgear and, more specifically, to an improved inflatable liner for sizing helmets and the like.
Proper sizing of protective headgear is essential for providing adequate support and protection to a user's head. Practicality dictates that a single helmet shell be adjustable to fit a wide range of head sizes so as to accommodate nearly any user's head.
Conventional inflatable liners have taken a number of forms. Inflatable bag type liners, for instance, have been used to size the helmet shell interior by filling a gap formed between a protective cushion or skull harness and the helmet shell. The inflatable bag is equipped with a valve positioned for cooperation with a corresponding hole in the helmet shell. Size adjustment is accomplished by inflating and deflating the liner.
Other inflatable liner systems utilize a pair of inflatable cushion units, one being a ringlike cushion for lining the top of the helmet interior and the other being an arc-like inflatable cushion for lining the front and side portions of the helmet. Each cushion has a separate valve requiring inflation of each unit individually.
Still other inflatable liners comprise one or more separate spoke-like inflatable crowns. An upper ringlike tube is connected to a lower but larger ringlike tube by an array of hollow spokes so that air may flow freely between the upper and lower tubes.
However, some of these liners do not provide effective sizing of the helmet. The inflatable bag type liner, for example, varies the volume of the helmet shell interior by simultaneously changing the interior diameters of the helmet on all sides, whereas changing the temporal circumference of the shell is all that is necessary for sizing the helmet. The inflatable bag also permits air to shift from the sides to the top of the helmet upon impact, causing the helmet to loosen thereby decreasing the protective capacity of the helmet.
In addition, the use of separate inflatable cushions has been found cumbersome and time consuming. In particular, such cushions not only require inflation but also require proper balancing of the pressure in each cushion to achieve uniform sizing of the helmet. These cushions have also been found costly to manufacture due to their complexity and the quantity of the materials necessary to achieve both protection and size variation.
Finally, should these conventional liners rupture from extensive use or impact, the entire helmet liner must be replaced at great expense to the user, since both protection and size variation are accomplished using a single complex liner system. Similarly, more durable liner materials have been found unsuitable for use with many such liner systems.
Thus, it is an object of the present invention to provide a simple, durable, efficient and economical inflatable liner for protective headgear which permits a single helmet shell to be adjusted to uniformly fit a wide rang of head sizes while providing crucial support and protection to the occipital protrusion and side portions of a user's head.
The above and other objects of the present invention are realized in a specific, illustrative embodiment of the inflatable liner which comprises a reinforced hollow expandable strip for the reception and storage of fluid, the strip having a selected size so as to line protective headgear and partially encircle a user's head, a reinforced hollow flap extension connected to the strip midsection for allowing the fluid to flow freely therebetween, a valve for controlling the passage of fluid to and from the inflatable liner, and pockets for maintaining uniform inflation of the strip and flap extension.